1. Field of the Invention
The present invention relates to an image forming apparatus which converts an image on a document to an electrostatic latent image by an electrostatic image forming process and develops the latent image through toner, and outputs a toner image on a sheet material.
2. Description of the Related Art
An image forming apparatus, for example, a copying machine includes a reading section for reading an object to be copied, that is, image data on a document, an image forming section for a copy image based on image data read by the reading section, and a paper feeding section for feeding transferring material on which the image formed by the image forming section is recorded, that is, a copy paper.
The reading section has a document table on which a document is mounted, and reads the image of the document as image data to be transmitted to the image forming section.
The material transporting section has material cassettes, which contain sheet materials, and a multi-feeder, which can feed the sheet material having a suitable size as required, and transports the sheet materials to the image forming section.
The image forming section includes a photoconductor on which an electrostatic latent image is formed in accordance with image data to be supplied through the reading section, a developing unit for developing the latent image by supplying toner to the latent image formed on the photoconductor, a transferring unit for transferring the toner image developed by the developing unit to the sheet material from the material transport section, and a fixing unit for fixing the toner image onto the sheet material.
The developing unit including toner for developing the electrostatic latent image and carrier for triboelectrically charging toner. The toner and carrier are mixed with each other, thereby the respective particles are charged to a predetermined polarity, and only toner is supplied to the electrostatic latent image.
The carrier and toner are mixed at a predetermined rate in advance to be used as developer. The developer is introduced into a predetermined position in the developing unit by a serviceman when the copying machine is operated for the first time. Such an introduction of the developer is called as a set-up. If the number of times of such a set-up is increased, there occur problems in which the service cost is increased, and the location where the copying machine is mounted and it surrounding portions become dirty. However, since it is known that qualification (physical property) of the developer is changed by the change of the temperature, the developer is airtightly provided, and the developer and the developing unit, which is generally incorporated into the copying machine, are separately transferred. Due to this, at present, it is indispensable for performing the set-up at the location where the copying machine is provided.
There has been proposed a technique in which the developer is introduced into the developing unit in advance and the entire developing unit is airtightly provided. However, there must be prepared an equipment for airtightly providing the entire developing unit and the structure in which the developing unit can withstand the transport of developer as being sealed. Due to this, there occurs a problem in that the manufacturing cost is increased.